Add golang keywords (zyedidia#1455)

* Add golang keywords

* Update runtime

Finish support for a fake cursor

Support rc tags in build version

Update nightly release script to not duplicate nightlies

Fix terminal emulator support

Improve command bar keybindings

The command bar now supports better keybindings:

CtrlA, CtrlLeft: start of line
CtrlE, CtrlRight: end of line
CtrlF, AltRight: next word
CtrlB, AltLeft: previous word
CtrlW, AltBackspace: delete previous word
CtrlV: Paste
Arrow keys as usual

These keybindings are not rebindable (maybe support will be added
in the future).

Replace home directory before performing SaveAs

Fixes zyedidia#820

Fix moving to end of line on cursor down

Update readme

install the snap with make (zyedidia#747)

* install the snap with make

* set the source-type to git, remove get

* remove extra space