Fixed: table cells were not initialized from xib settings

Previously, table view cells (non-view-based) were not being decoded with all of the available cell attributes in IB, and many attributes were hard-coded. In addition, there was a bunch of initialization code that has been made redundant by theming.

With this commit, decoding of all control classes has been refactored so that table view cells can use the same code, thus ensuring they decode all available cell attributes. In addition, the redundant code has been eliminated.

It is now possible to apply most table cell attributes such as font, color, alignment, sendsActionOnEndEditing, and so on, directly in IB.

Closes #1803

BREAKING CHANGE:
Changes have been made to table cell decoding in nib2cib. All xibs should be re-converted with `find . -name '*.xib' -exec nib2cib {} \;`.