Add fcvt, ecvt, gcvt functions.
tidied up environment conditionals
Ensure the linker pulls in static libraries containing exported functions.

Previously, an exported function contained in a library would not be found by
the linker if the library did not contain symbols transitively reachable from
main.
updated bad function formatting
Workaround for Chrome bug https://code.google.com/p/chromium/issues/detail?id=269679 : switch statement I added in isspace to make it faster seemed to cause the whole function to be optimized away. Replace with simple range checks in conditional expression.
Merge pull request #1479 from j4m3z0r/fast_isspace

Workaround for Chrome bug https://code.google.com/p/chromium/issues/deta...
fix static linker parsing bug
Merge pull request #1478 from inolen/function_spacing

updated bad function formatting
indentation fix
manually fill heap history in write targets of VFS.write|read into the heap
fix test_files
fix test_files_m
add missing return value in readdir_r
fix test_inet4
Merge pull request #1475 from inolen/env_tidy

tidied up environment conditionals in shell
Merge pull request #1474 from waywardmonkeys/cvt-functions

Cvt functions
ensure test runner cache names are valid filenames
 - select shouldn't return an error when the socket is valid, but disconnected
 - recv should return 0 once the socket has disconnected
 - send should set ENOTCONN once closed, and EAGAIN while connecting
 - updated tests to use O_NONBLOCK and better conform to coding standards
renamed socket tests
removed unused EMBED_SIDE define