Should finish addressing issue #524.

This reduces stack usage by 16 words (64 bytes) for stmhal/ port.

See issue #640.

?= operator does not do delayed expansion (unlike =).

toolchain fixes to enable cross compatibility

Build patches for FreeBSD (as discussed in the former pull request #666)

  cast error in MP_OBJ_NEW_SMALL_INT(). This is necessary for FreeBSD, where
  st_ino is of different size
- If MP_CLOCKS_PER_SEC is defined on the target host, simply define CLOCK_DIV
  as a fraction, regardless of the value of MP_CLOCKS_PER_SEC.
  FreeBSD uses a non-POSIX compliant value of 128 for CLOCKS_PER_SEC

  there are special tweaks and paths to be considered. Just provide some
  defaults, in case the values are undefined.
- py-version.sh does not need any bash specific features.
- Use libdl only on Linux for now. FreeBSD provides dl*() calls from libc.

unix: Fix path seperator used depending on OS

Bring the C and Python compute_hash functions into consistency

A couple of small fixes to run-tests

Fix str.modulo when precision is specified.

This behaviour follows Python 3.5 standard (in 3.4 it's a
DeprecationWarning which we'd rather make a TypeError).

Change comments (mainly URLs) to no longer specifically say Python 3.3

Some small fixed:

- Combine 'x' and 'X' cases in str format code.

- Remove trailing spaces from some lines.

- Make exception messages consistently begin with lower case (then
needed to change those in objarray and objtuple so the same
constant string data could be used).

- Fix bug with exception message having %c instead of %%c.

Remove tests that fail under CPython 3.5

Also, make sure that args to "*" format specifiers are bounds-checked
properly and don't lead for segfaults in case of mismatch.

See http://bugs.python.org/issue19995 for rationale. As micropython currently
aims for Python 3.3 compatibility I have not changed behaviour, but this
change allows the test suite to be run against a newer Python without having
spurious failures.

';' is the standard seperator used for paths in environment variables on Windows

Replace assert(0) with a self-documenting TODO string

As I suspected for a long time, for x86, register helper doesn't really make
any difference - there's simply not enough register to keep anything in
them for any prolonged time. Anything gets pushed on stack anyway. So, on
x86, uPy passed all tests even with empty reg helper. So, this setjmp
implementation goes as "untested".

remove `__doc__ =` and fix tweak doc diffs

micropython port for HydraBus

Two small changes

Once a double quote has been found, the subsequent discovery of a single quote
won't change behaviour at all, so don't bother looking for one.

Conflicts:
	README.md