tests: add Makefile target to run tests
misc: Get rid of decorators.decorate()

All it was doing is emulate functools.wraps()
misc: Get rid of profiling.py (unused)
misc: Get rid of xmlweapper.py (unused)
docs: Removed non-existing profiling module
argparse: fix up some bustage in get_moz_enUS
Imports: Add isort

- Add info for isort in development setup
- Add default config for isort behaviour
  - Ignore a number of files and folders
Imports: setup.py
Imports: sort tests/
Imports: sort tools/
Imports: sort translate/
Imports: sort translate/convert/
Imports: sort translate/convert/test_*
Imports: sort translate/filters/
Imports: sort translate/lang/
Imports: sort translate/misc/
Imports: sort translate/search/
Imports: sort translate/services/
Imports: sort translate/tools/

No sorting of test_* or commandline scripts
Imports: sort translate/tools/test_*