Fix installation bug

Now that we are importing backports.functools_lru_cache, importing the scanf module in setup.py to get the version info breaks if backports isn't already installed. Fix this by just parsing the version string directly instead of using the import machinery.

1.5.1: Fix Python 3.7 compatibility, improve caching

• Fixed Python 3.7 compatibility (scanf_compile broke in 3.7 due to differences in re.sub)
• Changed caching to functools.lru_cache for Python 3, backports.functools_lru_cache for Python 2.7 (thanks @eendebakpt!)
• Caching now takes collapseWhitespace into account (thanks @prittenhouse!)

v1.4: now python3 compatible, extractdata works properly

• Fix extractdata (was casting everything to floats)
• python3 compatibility
• Move README.md content to README.rst, removing pypandoc dependency from setup.py

Update PyPI metadata

1.3.3

Update metadata for PyPI