Use std::stringstream instead of snprintf() for double->string conversion

`snprintf()` will use the current `LC_NUMERIC` locale
for converting a double to a string,
which will use a `,` instead of a `.` in some locales (e.g. de_DE).
`std::stringstream` allows setting the locale to `"C"` to always get a `.`.
This occurs only for that `stringstream` instance; no global is
altered.
Merge pull request #7 from cdunn2001/fix-locale

Use std::stringstream instead of snprintf() for double->string conversion
ignore doxygen stuff
remove some sourceforge links
update docs for github
fix doxybuild.py paths
moved roadmap to wiki
doxygen changed
after doxygen -u
update docs for open-source-parsers org
README/NEWS links