Add separate folder for mainframer configs

[artem-zinnatullin]

In v2.x we'll add several files #19, #51 to allow customizations and integrations with basically any build system, also we're planning to move away from local.properties #50.

With that in mind, there is an option to put all mainframer configs into a separate folder (eg mainframer) where we could store all required files:

• ignorelocal (should be under VCS in most cases)
• ignoreremote(should be under VCS in most cases)
• personalconfig (or config (should NOT be under VCS in most cases)

[artem-zinnatullin]

@ming13, @dmitry-novikov thoughts?

[arturdryomov]

This structure should fit.

.mainframer/localignore
.mainframer/remoteignore
.mainframer/config