MIPS Support

These patches add support to examine MIPS Linux dumps. In order to create and load a MIPS profile, the latest version of pyelftools will be required, as versions before today didn't have support to parse MIPS dwarf sections.

As test platform, the OpenWRT Malta MIPS target can be build and run on qemu in system emulation. One important note, the default config will compile the kernel with reduced debug info, which means Rekall won't have the needed structure info to create a profile. Therefor when testing with OpenWRT, the generic config for the kernel needs a minor patch:

In target/linux/generic/config-3.xx

```
-CONFIG_DEBUG_INFO_REDUCED=y
+# CONFIG_DEBUG_INFO_REDUCED is not set
```

And another problem is due to a bug in QEMU, for which USE_MIPS16 has to be disabled, as gcc 4.8 will generate code that QEMU can't handle when that option is set (it's on by default).

http://www.eecs.harvard.edu/~margo/cs161/notes/vm-mips.pdf page 8 shows the mapping. But I just noticed I made a mistake, 8000 0000 - 9FFF FFFF is a direct map to 0000 0000 1FFFF FFFF but A000 0000 - BFFF FFFF also makes to the same range instead of continuing from 2000 0000 upwards.