Fixed vmem bug.

Somehow memory re-allocation seemed to work despite the fact that the comparison between the offset and end pointers where wrong. Corrected.
Improved UNIT_ASSERT_STRCMP() and UNIT_ASSERT_EQUALS().

In case function calls only returning valid arguments once were given as arguments, comparison would succeed, but the printout would be incorrect. This behavior was corrected by assigning to variables before performing comparisons or printouts.
Fixed issue where memory allocation would fail.
Added missing handling of memory allocation failure.
Added vsbuilder_getns() function.

Is used for acquiring the first n characters in string offset buffer, rather than all of them.
Added vsbuilder_getc() for retrieving single characters from beginning of builder string offset.
Comment fix.
Changed names and order of unit tests.
Removed newlines for increased clarity.
Added vsbuilder_peekc() and vsbuilder_peeknc() functions.
Added UNIT_ASSERT_STRNCMP() to UNIT.
Made sure UNIT assertions follows (expected, actual) order in comparisons.
Removed unnecessary variable assignments.
Re-factored vector string builder.

* Added vsbuilder_appendn().
* Replaced vsbuilder_getns() with vsbuilder_getn().
* vsbuilder_gets() no longer inserts '\0' into current string before returning.
* Added vsbuilder_skipc(), vsbuilder_skips(), and vsbuilder_skipn().
* Added vsbuilder_discardc() and vsbuilder_discardn().
* Removed unnecessary unit tests.
* Covered new functions in unit tests.