Add support for the Intel syntax produced by MSVC and ICC

[pleroy]

The changes to add the Intel syntax are rather large and required some restructuring. Here is an overview of the changes:

1. There is a new class, ParserX86Intel , to parse the Intel syntax. It produces instruction forms in the order of the syntax, i.e., the first operand is the destination.
2. In order to gather properties that don't depend on the syntax, such as the properties of the registers, there is a new class ParserX86 which is the superclass of ParserX86ATT and ParserX86Intel.
3. The matching of markers is now done on the instruction forms because it needs to be independent from details like the syntax of numeric literals that should only be known to the parser.
4. There is a new phase in between parsing and semantics, the "normalization". Its purpose is to align the instructions with the data found in the ISA and architecture models. For Intel, this obviously involves swapping the operands. But it also exists for the other parsers: for AT&T for instance, it does the mov/movq adjustment so that the rest of the code doesn't have to care about it.
5. The semantics is largely unchanged, except that it checks that the instructions it processes have been normalized.
6. There are, of course, extensive tests and data files.

Fix #106.