File permissions leak content to world

[Werkov]

Despite astrid explicitly sets umask 0x007, some files are created with 644 permissions. Those are perhaps created by forked processes (probably git) that don't honor/override the umask.
This has two negative impacts:

• files are write readable -- broken separation,
• files are group nonwritable -- broken automatic builds (should they overwrite such file).

Proposed solution:
Astrid should chmod after git operations,

Related: #11.