atplib#compiler#IsRunning: fix import statement
zathura: support for synctex

Patch by Sebastian Ramacher.
compile.py: flake
makelatex.py: flake
compiler.vim: code style
update README.md
Update .gitignore file
atplib/compiler.vim: typo in a comment

patch by Ignas Anikevicius
lualatex and xelatex compilers

patch by Ignas Anikevicius
options.vim CompierComp: use keys(g:atp_CopmilersDict)
build.vim: code style