build: switched to using poetry for `make build` (ActivityWatch#379)

* switched to poetry for installing project-wide dev dependencies (so we have versions locked)

* fixed appveyor and switched to dev version of PyInstaller

* updated submodules

* updated pyinstaller to use develop branch

* fixed CI on Windows and macOS where virtualenvs aren't set up

* updated appveyor config to install poetry *after* updating pip

* set up virtualenv on macOS and Windows builds

* updated submodule

* fixed virtualenv activation on Windows (travis)

* switched appveyor to 64bit Python and changed all python3 -> python, updated submodule with 64bit pyhook fix

* updated submodules

* added windows to allowed failures temporarily until timeout bug is fixed

Merge pull request ActivityWatch#375 from xylix/dev/fix-.dmg-naming

Add platform and arch info to .dmg

fixed issues with PyInstaller multipackaging by moving modules t… (Ac…

…tivityWatch#311)

fixed issues with PyInstaller multipackaging by moving modules to subdirs

Release v0.8.2

Release v0.8.1

updated submodules

Merge branch 'master' of github.com:ActivityWatch/activitywatch

Merge pull request ActivityWatch#246 from ActivityWatch/dev/v0.8.0b7

Make release v0.8.0b7