Removing unused macros

Probably results of copy and paste.

Refs #000.
Replacing macro with static const value

Making the name more descriptive. Removing multiple definitions of the
same macro.
Formatting according to the code standards

Refs #000
Using libMesh:invalid_uint for the case when the variable is not coupled.

Refs #000
9999999 is not the max for double

Refs #000
Removing a magic number

Refs #000
Merge pull request #4173 from andrsd/magic-numbers

Magic numbers