Override Execution Policy

Added the ability to override the machine\user execution policy. There
is a new dialog page that exposes the option.
Fixing unit test project.
Merge branch 'dev' of https://github.com/adamdriscoll/poshtools into dev
Better theme support.
Missed a file.

Missed a file with the last checkin.
Merge branch 'dev' of https://github.com/adamdriscoll/poshtools into dev
Data tips support.

Support for data tips and the watch window.
Read-Host support.
Read-Host -AsSecureString
Merge branch 'dev' of https://github.com/adamdriscoll/poshtools into dev