Fix bug 298 by enhancing signal and trace popup behavior
Populate signal popup combo box with signal name instead of probe name
Make trace popup combobox behave more user-friendly
Snapshot classes: Use vector instead of raw pointer

As a side-effect this turns a segfault (see bug #397) into a segfault
with a more usable message:

  terminate called after throwing an instance of 'std::bad_alloc'
    what():  std::bad_alloc
  Aborted (core dumped)
Only use one central .gitignore file.
Don't use Qt-defined keywords, they can cause problems with other headers.
Remove obsolete input module support.

This no longer works against libsigrok, which has an entirely new
API for input modules.
Remove broken assert().

This is no longer valid since c82c7e4 changed _data to a std::vector.
Make unit_size in Snapshot class unsigned.
Add missing default to switch/case block.
Rename 'probe' to 'channel' everywhere.
icons: Renamed probe.svg to channels.svg
Android: Bundle Qt libs with the APK
android: Minor whitespace fixes.
Make decoder popups close when pressing enter