Previous to this patch each time a bytes object was referenced a new
instance (with the same data) was created.  With this patch a single
bytes object is created in the compiler and is loaded directly at execute
time as a true constant (similar to loading bignum and float objects).
This saves on allocating RAM and means that bytes objects can now be
used when the memory manager is locked (eg in interrupts).

The MP_BC_LOAD_CONST_BYTES bytecode was removed as part of this.

Generated bytecode is slightly larger due to storing a pointer to the
bytes object instead of the qstr identifier.

Code size is reduced by about 60 bytes on Thumb2 architectures.

Recognize and handle "package not found" error.

The --pyboard param has been replaced by --target which defaults to
'unix'. Possible values at this moment are 'unix', 'pyboard' and
'wipy'. Now is also possible to select the baud rate of the serial
device when calling the script.

Thanks to Peter Hinch for contributing this.

This removes hard-coded DMA init params from dma_init(), instead defining
these parameters in a DMA_InitTypeDef struct that gets passed as an
argument to dma_init()
This makes dma_init more generic so it can be used for I2S and SD Card,
which require different initialization parameters.

This script is used by Jenkins to update the WiPy with the newly
built firmware before running the tests. It's not placed in the
common tools folder because it is very WiPy specific.

Addresses issue #1347

To make it the same as SPI and UART.

This is the standard way of doing things, one should construct a
peripheral object (even if it's a singleton).

See issue #1330.

The do_str() function is provided essentially as documentation to show
how to compile and execute a string.  This patch makes do_str take an
extra arg to specify how the string should be interpreted: either as a
single line (ie from a REPL) or as multiple lines (ie from a file).

Also, simplify dependencies info now that we no longer require GNU
readline.

This allows stmhal to be compiled with MICROPY_DEBUG_PRINTERS.

To comply with Python semantics.

Previous to this patch a call such as list.append(1, 2) would lead to a
seg fault.  This is because list.append is a builtin method and the first
argument to such methods is always assumed to have the correct type.

Now, when a builtin method is extracted like this it is wrapped in a
checker object which checks the the type of the first argument before
calling the builtin function.

This feature is contrelled by MICROPY_BUILTIN_METHOD_CHECK_SELF_ARG and
is enabled by default.

See issue #1216.