Issue title: Python Start-up Time Slow
 Issue body: The Python bindings are extremely slow on first-import.

```
$ pip install unicorn
Collecting unicorn
Installing collected packages: unicorn
Successfully installed unicorn-1.0.0rc3
$ for i in {1..10}; do time python -c 'import unicorn'; done
python -c 'import unicorn'  0.23s user 0.26s system 91% cpu 0.537 total
python -c 'import unicorn'  0.22s user 0.25s system 94% cpu 0.498 total
python -c 'import unicorn'  0.23s user 0.25s system 94% cpu 0.509 total
python -c 'import unicorn'  0.23s user 0.24s system 94% cpu 0.506 total
python -c 'import unicorn'  0.23s user 0.25s system 94% cpu 0.499 total
python -c 'import unicorn'  0.26s user 0.24s system 90% cpu 0.556 total
python -c 'import unicorn'  0.23s user 0.21s system 92% cpu 0.481 total
python -c 'import unicorn'  0.23s user 0.19s system 93% cpu 0.450 total
python -c 'import unicorn'  0.23s user 0.20s system 93% cpu 0.463 total
python -c 'import unicorn'  0.24s user 0.20s system 93% cpu 0.465 total
```
 Comments: 
 Comment 0: Can you investigate why?
 Comment 1: I experienced the same. I think it had to do with the unicorn binary with various arch support resulting in a 20mb file. Zach, try to compile unicorn with just the arch you are using only. For instance if you want just x86 that would trip the size to just 3mb.
 Comment 2: I'm using Unicorn as directly compiled from `pip install unicorn`. 

It doesn't make any sense at all to "only" compile-in support for individual architectures, nor should it incur any performance penalty just to *import* the Python module, regardless of which architectures are compiled-in.
 Comment 3: It's 5x slower for me to import from an egg.
{'source': 'GithubIssues', 'repo_name_with_owner': 'unicorn-engine/unicorn', 'issue_id': 210586114, 'repo_stars': 5897.0}