Testing a new Camera acceleration curve.

This replaces the previous PrecisionCenter acceleration
curve. It is much more accurate and gradual after the first
inflection point. Related to issue #92.
Fixed invalid pointer issue for hold events.
Fixed issue with set selection changes not resetting older assignments.
Renamed Camera curve to Enhanced Precision and made it the default. Abstracted more methods in MouseSettingsDialog. Change to remove warning for spring preview in on Windows.
It appears that Qt::WA_PaintOnScreen is not needed for Qt5.
Changed method connected to acceleration combobox for new curve.

The method no longer relies on the combobox index. The appropriate
curve will be determined from a different method and
changeSensitivityStatus will check the curve type.
Edited README. Made a small change to more strictly enforce when sensitivity spinbox is enabled.
Updated base translation files.
Change window size of MainSettingsDialog.
Edited tooltip for Key Repeat.
Updated to version 2.3.1.
Fixed issue with old profiles not being usable by the program.

The profile migration class was flawed since old profiles
with a lower configversion than the most recent spec would
cause a migration to be started. However, if the configversion
of a profile was version 5 or older, the old data was discarded
with nothing to replace it so no bindings would be loaded into the
program.
Updated to version 2.3.2.
Initial CMake build support. Related to issue #86.
Added more conditions for checking Qt versions. Tested on Debian Wheezy.
Minor tweaks for AdvanceButtonDialog.

Make sure [NO KEY] is displayed when new empty slot is added
under Windows. Adjust button widget size.
Tweaked some CMake rules that are used on Windows.
Cache recent config list upon gamepad removal. Switch watched signal in AdvanceButtonDialog.