Changes

Added a closing `// namespace UI` here and there (#1592).
 (commit: b34d712)

Some minor cleaning up.
 (commit: a86fb6e)

Some minor cleaning up.
 (commit: 08e0f1e)

Replaced `virtual` with `override` in overridden methods (#1592).
 (commit: 47c7ac4)

Replaced instances of `const bool &` with `bool` (#1592).
 (commit: f0107d5)

Replaced instances of `const double &` with `double` (#1592).
 (commit: c7278e7)

Replaced instances of `const qint64 &` with `qint64` (#1592).
 (commit: bbc1bf2)

Replaced instances of `const quint64 &` with `quint64` (#1592).
 (commit: 4ef87af)

Replaced `Qt::CTRL` with `Qt::ControlModifier`, `Qt::SHIFT` with
`Qt::ShiftModifier`, `Qt::ALT` with `Qt::AltModifier` and `Qt::META`
with `Qt::MetaModifier` (#1592).
 (commit: 82d940c)

Some work on using the "new" signal/slot syntax (#1592).
 (commit: f222435)

Some minor cleaning up (#1592).
 (commit: a81dcb9)

Some work on using the "new" signal/slot syntax (#1592).
 (commit: 6a19d8d)

Some work on using the "new" signal/slot syntax (#1592).
 (commit: 843cf63)

Some minor cleaning up (#1592).
 (commit: 5062675)

Temporarily enable sample plugins, test plugins and tests.
 (commit: adbe687)

Some work on using the "new" signal/slot syntax (#1592).
 (commit: b28369e)

Some work on using the "new" signal/slot syntax (#1592).
 (commit: bb1ff61)

Some work on using the "new" signal/slot syntax (#1592).
 (commit: badd5a5)

Some work on using the "new" signal/slot syntax (#1592).
 (commit: be53e52)

Some work on using the "new" signal/slot syntax (#1592).
 (commit: 3608009)

Some minor cleaning up (#1592).
 (commit: 9f15ced)

Some work on using the "new" signal/slot syntax (#1592).
 (commit: 9b70ad6)

Some minor cleaning up (#1592).
 (commit: 16ccb42)

Some work on using the "new" signal/slot syntax (#1592).
 (commit: 6452f48)

Some minor cleaning up (#1592).
 (commit: bdeaa02)

Some work on using the "new" signal/slot syntax (#1592).
 (commit: c81386f)

Some minor cleaning up (#1592).
 (commit: 01ba2d3)

Some work on using the "new" signal/slot syntax (#1592).
 (commit: 2657147)

Some minor cleaning up (#1592).
 (commit: c41af1f)

Some minor cleaning up (#1592).
 (commit: ff96cce)

Some minor cleaning up (#1592).
 (commit: 7bc6041)

Some work on using the "new" signal/slot syntax (#1592).
 (commit: c908059)

Removed a file that we forgot to delete at some point.
 (commit: 63167c5)

Some minor cleaning up.
 (commit: 165087b)

Some minor cleaning up (#1592).
 (commit: df284b1)

Some minor cleaning up (#1592).
Removed our use of full namespaces since we don’t need them with the new
signal/slot mechanism.
 (commit: 626d02a)

Some minor cleaning up (#1592).
 (commit: f0e4e2c)

Some minor cleaning up (#1592).
 (commit: 1f17877)

Some work on replacing automatic signals on_XXX_YYY() with a proper
connection (#1592).
 (commit: 3b94f42)

Some work on replacing automatic signals on_XXX_YYY() with a proper
connection (#1592).
 (commit: 7c30c01)

Some work on replacing automatic signals on_XXX_YYY() with a proper
connection (#1592).
 (commit: 4a04543)

Some work on replacing automatic signals on_XXX_YYY() with a proper
connection (#1592).
 (commit: 995e63a)

Some minor cleaning up (#1592).
 (commit: ba7935d)

Redisable our sample plugins, test plugins and tests.
 (commit: d293a03)

Some minor cleaning up (#1592).
This ensures that we can build QSctintilla and still have our Editing 
widget to build fine on Linux
 (commit: dea4690)