[trunk] Prefer the new style cmake: add_test command

Fixes issues 258
[trunk] Make sure to handle ret value in test
[trunk] Make sure to handle ret value, and properly initialize output file
[trunk] Fix warning about signed/unsigned mismatch
[trunk] Fix two simple warnings about sign mismatch
[trunk] Fix a simple mem leak
[trunk] improve test suite by checking against a reference md5
[trunk] add test demonstrating a regression in 1.5.0 and up. Update issue 205
[trunk] Make sure to always output pgx file. Handle case where multiple pgx files are generated. Fixes all tests.
[trunk] add missing private lib. Update issue 223
[trunk] Run sumatrapdf test cases