Added mpileup tests
Mpileup test in Makefile
Add -b parameter to samtools merge manpage
Update samtools.1
Match style for FILE option
Alternate syntax for samtools merge.

Providing a FILE to the -b option for samtools merge overrides any file selection made at the command line, I have added an alternative syntax line in the documentation to try and clarify this.
Alternate syntax for samtools merge in stderr message
Clarify list is not a literal
Match samtools merge manpage and stderr syntax
Fix getline memory leak in test_bam_translate

getline resizes *res with realloc if *len is smaller than
the number of characters read from the stream on that call.
Setting *len to 0 before each test thus causes getline to
use realloc on *res to increase its size by the number of
characters read for each test, despite the fact it is already
of the correct size.
Fix memory leak in test_rtrans_build

trans_tbl_destroy call missing for second element of tbl_1 (trans_tbl_t) array.
Fix memory leak in test_trans_tbl_init

Missing call to regfree to free memory allocated to pattern buffers by regcomp.
Add missing fclose of orig_stderr to test_bam_translate
Fix getline memory leak in test_filter_header_rg
Fix getline missing fcloses in test_parse_args
Add missing frees to test_parse_args
Free char* in parsed_opts in test_parse_args
Add code to separate out stdout and stderr in testing

Previously the output of these was merged by redirection.

Signed-off-by: Martin O. Pollard <mp15@sanger.ac.uk>
Make merge take union of commandline and -b inputs and test merge code

Make merge command take union of command line input file and those listed in
-b's fofn.
Add tests for merge code

Signed-off-by: Martin O. Pollard <mp15@sanger.ac.uk>
mpileup: Long options; Custom DP,DV,DP,DP4 format fields on output