Update maintainer information and currently used sources
Leave $pkgver in 0.0.0, makes easy to update when there are new PKGBUILD

$pkgver is updated automatically, so there's no point in change it every
time. With this, changes only happen when there's a change in the
PKGBUILD (like the source, or some needed patch). This also allows us,
to leave the packaging ssues asides from the ones regarding the actual
build of the packges.
Add conclict with otf-powerline-symbols-git package
Bump python-{2,3}-powerline-git packages to `0.0.0-2`.