add headerless mode

Approved-by: Jose Rodriguez <boriel@gmail.com>

Feature/headerless

This must be done every time the main() function is called.

The global OPTIONS container now allows any type
(None was not always possible) using the options.ANYTYPE
value as type_ parameter.

This adds test_basic, test_asm and test_prepro, which
are run by py.test (and tox), meaning every test
is now atomic and allows coverage analysis.

api.config.init() was not being called when
zxbasm was being invoked from the command line or with its
main() function. Fixed.

This allows py.test to detect it.

This allows to specify -- test_xxx in tox from the command line.

This is a momentanous workaround to avoid E722 and E741 (which
previously were only warnings).
This is done because most of the backend part is gonna be
refactored almost from scratch.

When creating temporary directories, py.test might fail
when scanning them as these directories are efimeral
and not for testing. So they're now excluded.

Also updates to python 3.6

Chore/test improvement

Chore/test improvement

Approved-by: Jose Rodriguez <boriel@gmail.com>

Now it finish at 10 points

update pong example

Approved-by: Jose Rodriguez <boriel@gmail.com>

Chore/example

Using POKE before an ASM region in a fastcall
function might overwrite the registers used as
parameters. Fixed.

Thanks to @Emook (D. Saphier) for the report. ;)

MemCopy library function was not correctly working. Fixed.
Also added MemMove() which allows overlapping blocks.

Thanks to @Emook (D. Saphier)

bugfix: fix memcopy library function

Approved-by: Jose Rodriguez <boriel@gmail.com>

bugfix: fix read / write errors

Approved-by: Jose Rodriguez <boriel@gmail.com>

Bugfix/esxdos

Bugfix/memcopy

Add basic HTML coverage

Add basic HTML coverage

Approved-by: Jose Rodriguez <boriel@gmail.com>

Removes .MSI reference, and put clearer instructions.
Also adds logo (by @haplo. Thanks!!)
Thanks to @Hark0 for his suggestions.

update README.md file

Approved-by: Jose Rodriguez <boriel@gmail.com>

Doc/readme

Bump version: 1.8.7 → 1.8.8

Approved-by: Jose Rodriguez <boriel@gmail.com>

This cmd line option allows the compiler to
parse and analyze the source code without emitting
any code.

This will allow to invoke zxb with --org=0xC000 for example.

Feature/base org hexa

Approved-by: Jose Rodriguez <boriel@gmail.com>

Defining a var like DIM p = @A(3, 4) being var a an
array crashed the compiler. Fixed.

This one checks the array element position is correctly
computed (chained multiplication).

The flag --debug-array emited wrong code.
The Array calculation routine has been optimized (a little) and
now does the check correctly.

Also de translator was not correctly emiting the IC.

Note that both #pragma and #define must be used since
the array checking requires such define that might not be
declared at the beginning.

Bugfix/const arr crash

Approved-by: Jose Rodriguez <boriel@gmail.com>

Parsing some READ sentences with semantic errors crashed the
compiler. Fixed.

bugfix: read crash

Approved-by: Jose Rodriguez <boriel@gmail.com>

When reading an array element, the args must be computed only
once or array-base will be applied several times.

Bugfix/read array base

Approved-by: Jose Rodriguez <boriel@gmail.com>

When no DATA sentence is used, but READ is, a missing
label error shows because a default one is not output
to signal the beginning of the DATA zone.

Bugfix/data missing label

Approved-by: Jose Rodriguez <boriel@gmail.com>

This way INT is more compatible and behaves
like INT function in Sinclair BASIC

make int to behave as BASIC INT

Approved-by: Jose Rodriguez <boriel@gmail.com>

Bump version: 1.8.8 → 1.8.9

Approved-by: Jose Rodriguez <boriel@gmail.com>

When using ORG several times, if the assembled regions overlaps,
sometimes declaring a label on top of an existing (assembled) instruction
crashed the ASM. Fixed.

Fix error on multiple ORG

Approved-by: Jose Rodriguez <boriel@gmail.com>