Merge pull request #2 from igagnidz/master

Wrong date in Excel [because of Lotus 123 bug - wow, that's awesome]
bump patch
store strings in the shared strings table instead of inline.
use t='s' instead of inlineString for empty cells.
standardize folder hierarchy
no reason for a separate XlsxWriter::Document class... just use XlsxWriter.new
write rows to disk as they are provided
write shared strings to disk as they are created
clarify and DRY the whole cell-type thing
what's been up
Render BigDecimal and Rational as decimal
bump minor
Merge pull request #1 from seamusabshere/master

merge with upstream