Strip whitespace from cells (R parsing code).

Fixes #1132.
Only table innards are stripped

Matches more closely with what we're doing in QIIME parsing code.
-e is now used on #!/bin/bash
Modified check_id_map.py to by default not strip leading/trailing whitespace and quote characters. Other script calls to map parsing function should still strip these. Modified test_check_id_map.py to test this case of mapping file format. Added some details to doc/documentation/file_formats.rst to reflect some of the stripping to be expected in mapping files.
Merge pull request #1136 from wasade/issue1104

-e is now used on #!/bin/bash
Merge pull request #1134 from jrrideout/issue-1132

Strip leading/trailing whitespace from cells (R parsing code)
Modified documentation/file_formats.rst to reflect quote character/whitespace stripping
Modified documentation/file_formats.rst to reflect quote character/whitespace stripping
Merge pull request #1138 from walterst/check_id_map_sampleid_whitespace

Modified check_id_map.py to by default not strip leading/trailing whites...