Implement IsSmartTagSessionActive in mock broker for insert mode tests.
Bug fixes for Ctrl+T in insert mode.
- Fix ShiftLineRight in insert mode to actually indent on empty lines.
- Fix ShiftLineRight to round leading spaces up to a multiple of the shift width.
- Add unit tests for the above cases.
Merge pull request #1217 from ricksladkey/bug-ctrl-t-insert

Bug fixes for Ctrl+T in insert mode.