Replaced Unicode non-ASCII codepoints from x86.csv

The presence of Unicode non-ASCII codepoints caused building to fail on Ubuntu 13.10 with default package versions. (That is, system built according to instructions in repo.)

All of these characters appear to be in the descriptions of the instructions, so this shouldn't have any impact on correctness.

Here's the script I used to fixup x64.csv; licensed CC0 if you want to incorporate in ODS-extraction process.

```
#!/usr/bin/python
"""Replace some Unicode characters in x64.csv"""
import sys

REPLACEMENTS = [
  (u'\u03c0', u'pi'),
  (u'\u2013', u'-'),
  (u'\u2014', u'-'),
  (u'\u2217', u'*'),
  (u'\u201d', u'"'),
  (u'\u201c', u'"')]

def do(ifn, ofn):
  with open(ifn, 'rb') as f:
    u = f.read().decode('utf-8')

  for c, repl in REPLACEMENTS:
    u = u.replace(c, repl)

  s = u.encode('ascii')

  with open(ofn, 'wb') as f:
    f.write(s)

if __name__ == '__main__':
  do(sys.argv[1], sys.argv[2])
```