Merge pull request #153 from zivchang/next

[bug fixing] PTSDK-1405
[Bug fixs] PTSDK-1337
- Make the overlay not cover Timezone part of Network Management panel when network is unavialable.
Merge pull request #154 from jacobchen/next

[Bug fixs] PTSDK-1337
bugfix: PTSDK-1385, 1180
 - allow addChangeListener/removeChangeListener for callhistory.read
[bug fixing] PTSDK-1371

fix SCREEN_OFF can be allowed to request issue.
SCREEN_OFF state connot be requested but only be used in the state change callback