Use singleton mode for hotkey callbacks.

I hope this is the last one.

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

- detach event handler before exiting
- eliminate UI and non-UI exception handling race
- rework exception message

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

- enlarge timeout to 10 seconds
- detach event handler before exiting
- output log if success

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

Workaround for slow computers

Credit to GangZhou's code

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

Design:

Use the plain string for both config and hotkey parsing
and make use of KeyConverter, ModifierKeysConverter
to make it more rubust.

Find corresponding label (to display operation result) and callback (to do the real work) based on textbox name. In this case, they should be named as `<Feature-Name><Control-Name>`.

ShowLogsTextBox,
ShowLogsLabel,
ShowLogsCallback.

If this requirement doesn't meet, throw an exception at runtime.

Logic:

How to input keys:
1. put focus in the corresponding textbox
2. press the key combination you want to use
3. when you think it is ready, release all keys
4. the textbox shows your input

How to change keys:
1. put focus in the corresponding textbox
2. press BackSpace to clear content
3. re-input new one

How to deactivate:
1. clear content in the textbox
2. press OK button

Meaning of label color:
- Green: this combination is not occupied by other programs and register successfully
- Yellow: this combination is occupied by other programs and you have to change to another one
- Transparent without color: initial status

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

- Only use one instance of LogForm

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

- Change controller based on power mode
- Stop before exiting

Based on GangZhuo's code

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

- Running on Windows Vista or above

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

- use null conditional access in case some connections been
  cancelled unexpectedly and may cause null reference exception
- Refine error message
- use conditional operator to simplify some code

Signed-off-by: Syrone Wong <wong.syrone@gmail.com>

Squashed commit of the following:

commit e280c2385c
Merge: 579039f 87aa9eb
Author: Gang Zhuo <gang.zhuo@gmail.com>
Date:   Wed Mar 16 04:02:27 2016 -0400

    Merge remote-tracking branch 'origin/master'

commit 579039fe40
Author: Gang Zhuo <gang.zhuo@gmail.com>
Date:   Fri Mar 4 21:45:23 2016 +0800

    log unhandle exception

commit 8d863f1d5f
Author: Gang Zhuo <gang.zhuo@gmail.com>
Date:   Fri Mar 4 21:44:54 2016 +0800

    fix Availability Statistics

commit b3ce1c698a
Author: Gang Zhuo <gang.zhuo@gmail.com>
Date:   Fri Mar 4 21:07:54 2016 +0800

    tiny refactor

commit 0f7d39e27e
Merge: bd7078a b01aced
Author: Gang Zhuo <gang.zhuo@gmail.com>
Date:   Fri Mar 4 20:02:58 2016 +0800

    Merge remote-tracking branch 'origin/master'

commit bd7078aa4f
Author: Gang Zhuo <gang.zhuo@gmail.com>
Date:   Fri Mar 4 20:01:58 2016 +0800

    tiny refactor

commit 49adb95b6e
Author: Gang Zhuo <gang.zhuo@gmail.com>
Date:   Fri Mar 4 03:44:26 2016 -0500

    log more Ping information for debug

commit 2aa0620ddd
Author: Gang Zhuo <gang.zhuo@gmail.com>
Date:   Fri Mar 4 03:04:10 2016 -0500

    reduce 3rd packages

[solve conflicts and squash to make history clean]
Signed-off-by: Syrone Wong <wong.syrone@gmail.com>