v3.1.4

Patch release with miscellaneous bug/doc/build fixes.

• [#229] Remove some simple typos in the code
• [#228] Added missing check _M_IX86 or _M_X64 when using __lzcnt.
• [#224] SolveNormalizedCubic fix to return proper real root
• [#223] Add docs target only if not a subproject
• [#222] Fix docs race condition and make installation optional
• [#220] Remove dead PyImath code and references to ilmbase
• [#219] Use equalWithAbsError instead of equal operator for float
• [#218] Fix sphinx warnings and man page filenames
• [#215] Adding missing stdexcept header
• [#214] Use .x instead of operator[] for better SIMD auto-vectorization
• [#213] Remove extra project layer for the pyimath code
• [#209] Successor/predecessor functions use isnan() and isinf()
• [#207] Fix python imath export
• [#202] Cuda safety fixes
• [#185] Sort Imath source files
• [#182] Fix formatting in release notes