Add more missing steps to the build instructions.

- Mantle must also be added to the project workspace in the same manner as
  ReactiveCocoa. More so both ReactiveCocoa and Mantle must be added to the
  copy frameworks build phase or else the application will not start.
- The copy phase is a bit tricky as it involves quite a few steps to get it
  right, thusly I added a section describing how to do it.

Signed-off-by: Aron Cedercrantz <aron@cedercrantz.se>
Improve the layout of dervied data location.

Signed-off-by: Aron Cedercrantz <aron@cedercrantz.se>
Remove unnecessary step in copy framework guide.

Signed-off-by: Aron Cedercrantz <aron@cedercrantz.se>
Improve the wording in the getting started guide.

Signed-off-by: Aron Cedercrantz <aron@cedercrantz.se>
Fix minor issues with copying the frameworks guide.

Signed-off-by: Aron Cedercrantz <aron@cedercrantz.se>
Fix notes.

Signed-off-by: Aron Cedercrantz <aron@cedercrantz.se>
Merge pull request #69 from rastersize/even-better-build-instructions

Add more missing step to the build instructions.