Capitalization, list model and room header work

- Standardized capitalization for variables and file names everywhere in
  QML and JS, get rid of mixed camelCase/snakeCase,
  use camelCase like everywhere in Qt

- ListModel items are now stored and returned as real QObjects with
  PyQt properties and signals.
  This makes dynamic property binding a lot easier and eliminates the need
  for many hacks.

- New update(), updateOrAppendWhere() methods and roles property
  for ListModel

- RoomHeader now properly updates when the room title or topic changes

- Add Backend.pdb(), to make it easier to start the debugger from QML

Makefile

@@ -6,12 +6,14 @@ PKG_DIR = harmonyqml
 PYTHON  = python3
 PIP     = pip3
 PYLINT  = pylint
+MYPY    = mypy
 VULTURE = vulture
 CLOC    = cloc
 
 ARCHIVE_FORMATS = gztar
 INSTALL_FLAGS   = --user --editable
 PYLINT_FLAGS    = --output-format colorized
+MYPY_FLAGS      = --ignore-missing-imports
 VULTURE_FLAGS   = --min-confidence 100
 CLOC_FLAGS      = --ignore-whitespace
 
@@ -47,6 +49,8 @@ upload: dist
 test:
 	- ${PYLINT} ${PYLINT_FLAGS} ${PKG_DIR} *.py
 	@echo
+	- ${MYPY} ${PKG_DIR} ${MYPY_FLAGS}
+	@echo
 	- ${VULTURE} ${PKG_DIR} ${VULTURE_FLAGS}
 	@echo
 	${CLOC} ${CLOC_FLAGS} ${PKG_DIR}