Shell escaping isn't right

[rmanthorpe]

Shell escaping isn't right. This is also part of the problem with using regex as it stands. To see the problem, try greping for some regex! I think it might be best not to use shell-quote and just do a minimal quoting ourselves. I think a rough idea of how to do this better is:

• On Linux & Mac: Surround by double quotes then we just need to handle $, ` , " and \.
• On Windows: Surround by double quotes and I don't think you need to escape anything.