tests: Force skip of LE test on non-LE arch; improve run-tests-exp.sh.
tests: Add missing "import sys".
tests: Skip ffi_float.py if module ffi is not available.
windows: mingw32 gcc doesn't define endianness macros, so just assume little.

Specifically, at least Ubuntu's i586-mingw32msvc-gcc doesn't supply
__LITTLE_ENDIAN__ and friends. And as it's safe enough to assume that
Windows is only little-endian, then it's defined unconditionally,
instead of duplicating detection logic in py/mpconfig.h (or adding
windows-specific defines to it).
travis: Install realpath, required for teensy build.
Allow real memory errors (from locked gc) to be reported with traceback.
Updating README.md to include the fact that the Unix build requires pkg-config to build the FFI module.
Make lexer fail gracefully when memory can't be allocated.
py: Add #if guard around gc-specific code.
Merge branch 'dhylands-memory-error'
Merge pull request #897 from tomvonclef/master

Updating README.md. The Unix build requires pkg-config for FFI.
Merge branch 'lexer-crash' of https://github.com/dhylands/micropython into dhylands-lexer-crash
py: Add further checks for failed malloc in lexer init functions.
Merge branch 'dhylands-lexer-crash'
Merge branch 'master' of github.com:micropython/micropython
examples: Rename unix socket examples to have more precise naming (http).
unix: Rename "microsocket" module to "usocket".

Per new conventions, we'd like to consistently use "u*" naming conventions
for modules which don't offer complete CPython compatibility, while offer
subset or similar API.
Merge pull request #899 from pfalcon/usocket-rename

unix: Rename "microsocket" module to "usocket".
stmhal: Add pyb.stop() and pyb.standby() functions.
Add support for complimentary channel output and deadtime.

This patch enables output on the complimentary channels (TIMx_CHyN).
For timers 1 and 8, deadtime can also be inserted when the channels
transition. For the pyboard, TIM8_CH1/CH1N and TIM8_CH2/CH2N can
take advantage of this.