Fix shader parse error with \r new-lines

[VReaperV]

Fixes a shader stage parsing error on https://users.unvanquished.net/~sweet/pkg/map-monk_0%2B0.dpk.

[slipher]

gantry is another map exhibiting this issue.

Counting both \r and \n as newlines will mess up the line counter for other parsers for files using CRLF. How about replacing \r with \n in COM_Compress instead? That function is used only for shaders, and the shader parser doesn't use line numbers.

[VReaperV]

That makes sense, I changed this to modify COM_Compress() now instead.

[slipher]

LGTM