share/README: reformatted to group Python modules into types of function.
Added new module share/simple_xls.py (nicer programmatic interface for making XLS spreadsheets).
RNA-seq/bowtie_mapping_stats.py 1.1.3: substantial update, now also works with Bowtie2 output.
RNA-seq/bowtie_mapping_stats.py: cosmetic updates to usage message and comments.
RNA-seq/README: updated to reflect changes to bowtie_mapping_stats.py.
Updated ChangeLog.
share/simple_xls.py 0.0.7: update with new methods and some performance optimisations.

Adds various new methods to insert and append columns and rows, and improve internal
book-keeping in order to give significant performance gain over previous version.
RNA-seq/bowtie_mapping_stats.py 1.1.4: update how output spreadsheet is generated.
RNA-seq/bowtie_mapping_stats.py: 1.1.5, now correctly handles paired-end Bowtie2 output.