beware to use gtk+ v3.18 not 3.20

release 3.0.1

release note for 3.0

reno's collapse_pre_releases does not seem to work for
beta version... so, release note is manual

update NEWS and prepare release note for beta2

update docs and release notes

update release note

update docs and release notes

Merge pull request Guake#1048 from Stibbons/guake3_rework_build_system

clean build system for guake 3 + update translation system

update README

Merge pull request Guake#1045 from zqb-all/master

Update Chinese translation