fix compiler warning about use of uninitialized stucture

* added initialization of precision ( 0 => use sass default precision )
fix compiler warnings about missing end of file newlines

* added terminal newlines to util.{ch}pp
move ruby program to variable RUBY_BIN
use $(MAKE) variable
move ruby program to variable RUBY_BIN and use $(MAKE) variable
Option: Map URL is now disableable. (#357)
SourceMap: Fix relative paths for Windows. (#242)
It required converting all paths to lower-case,
the rest of the implementation was there.
This lower-casing is not locale-aware, as NTFS is
all case-sensitive when it goes beyond ASCII.
Interface: Use input filename to contruct the
default value of output.
Adds resolved file path normalization

Replace back slashes with forward slashes on windows.
Since get_cwd is normalized the same way, we need to
normalize this path too. Otherwise resolve_relative_path
will not work correctly on windows.
Adds better json encoding for source map output
Merge pull request #416 from rivy/fix-explicit.init

fix compiler warning about use of uninitialized structure
Merge pull request #417 from rivy/fix-EOF.newlines#2

fix compiler warnings about missing end of file newlines
Merge pull request #422 from sbertrang/small-makefile-improvements

Small makefile improvements
Merge pull request #440 from am11/master

Option: Map URL is now disableable (#357)
Merge pull request #441 from am11/issue-242

SourceMap: Fix relative paths for Windows (#242)
Merge pull request #451 from mgreter/source_maps_win_rel_paths

Problem with relative path on windows and source maps