LogicSignal: Removed redundant calls to match_action
LogicSignal: Renamed action_match and match_action
LogicSignal: Refactored get_trigger_types
icons: Added trigger markers
LogicSignal: Added an icon cache
LogicSignal: Added trigger markers
Fix saving of channel names in .sr files.

This closes bug #490.
Minor whitespace fixes.
Example channel names: Consistently use all-caps.

Rename Tx->TX and Rx->RX to be consistent with the other names.
CMakeLists.txt: Fix whitespace, cosmetics.
README: Update status.
INSTALL: Update and fix build requirements.
test: Disable all unit tests for now (all of them are broken).
decoderstack.cpp: Fix incorrect #inludes.
Build system: Fix issue with unit tests, simplify code.

Drop some unneeded lines from test/CMakeLists.txt. Most of the variables
are inherited from the main CMakeLists.txt file. This reduces the amount
of duplicated code and the likelyhood that the two CMakeLists.txt files
get out of sync.

This fixes the following issues when building the unit tests
(related to mixing Qt4 and Qt5 apparently):

  [ 69%] Building CXX object CMakeFiles/pulseview.dir/signalhandler.cpp.o
  [...]/test/__/pv/moc_sigsession.cxx:13:2:
  error: #error "This file was generated using the moc from 4.8.6. It"
   #error "This file was generated using the moc from 4.8.6. It"
    ^
  [...]/test/__/pv/moc_sigsession.cxx:14:2:
  error: #error "cannot be used with the include files from this version of Qt."
   #error "cannot be used with the include files from this version of Qt."
    ^
  [...]/test/__/pv/moc_sigsession.cxx:15:2:
  error: #error "(The moc has changed too much.)"
   #error "(The moc has changed too much.)"
    ^
  [...]/test/__/pv/moc_sigsession.cxx:64:7:
  error: ‘QMetaObjectExtraData’ does not name a type
   const QMetaObjectExtraData pv::SigSession::staticMetaObjectExtraData = {
         ^
  [...]/test/__/pv/moc_sigsession.cxx:70:37:
  error: ‘staticMetaObjectExtraData’ was not declared in this scope
         qt_meta_data_pv__SigSession, &staticMetaObjectExtraData }
                                       ^
  [...]/test/__/pv/moc_sigsession.cxx:
  In member function ‘virtual const QMetaObject* pv::SigSession::metaObject() const’:
  [...]/test/__/pv/moc_sigsession.cxx:79:71:
  error: conditional expression between distinct pointer types
  ‘QDynamicMetaObjectData*’ and ‘const QMetaObject*’ lacks a cast
       return QObject::d_ptr->metaObject ? QObject::d_ptr->metaObject : &staticMetaObject;
                                                                         ^
  [...]/test/__/pv/moc_sigsession.cxx:80:1:
  warning: control reaches end of non-void function [-Wreturn-type]
   }
   ^
  test/CMakeFiles/pulseview-test.dir/build.make:1362: recipe for target
  'test/CMakeFiles/pulseview-test.dir/__/pv/moc_sigsession.cxx.o' failed
  make[2]: ***
  [test/CMakeFiles/pulseview-test.dir/__/pv/moc_sigsession.cxx.o] Error 1
  CMakeFiles/Makefile2:110: recipe for target
  'test/CMakeFiles/pulseview-test.dir/all' failed
  make[1]: *** [test/CMakeFiles/pulseview-test.dir/all] Error 2
  make[1]: *** Waiting for unfinished jobs....
test/CMakeLists.txt: Fix file list, fix -DENABLE_TESTS=y build.

The build is now fixed for -DENABLE_TESTS=y, but re-enabling the
actual unit tests (and potentially other issues) will need more work.
Removed cotire

cotire has proven itself to be counter-productive. It rebuilds the pre-compiled
header after any header in pulseview is modified causes a complete rebuild of
all of PulseView. Also, the pre-compiled header contains a union of all the
includes of all source files, which masks errors where source files are missing
needed includes.
.gitignore: Added .ninja_deps
Session: Renamed files to match class name
Ruler: Moved calculate_tick_spacing into View