Make/modify build chain

[kateliev]

After todays build i realized that some updates to our tools as well as making some simple ones will do us good.

To do:

Preflight tool:

• [x] Add .loclBGR and *.alt to safe suffix list;
• [x] Add automated Round, Decompose, Convert to TT actions (and button);

Unify CLI Build steps under single shell script:

• [x] Powershell for Win users;
• [x] Bash for Mac/Linux users;

[kateliev]

@tphinney this is now done. Each shell script contains all the steps listed after UFO export in documentation/compiling_fonts.md including the font validation step. Let me know if that one is actually needed. For now it is included.

[kateliev]

These are done, closing :)