Replace single -d:ssl switch with -d:libressl and -d:openssl

v0.3.0

Install only openssl, minus docs and other unnecessary things

Now the Nim file does not need to be the last parameter. Also multiple
Nim files can be specified.

v0.2.0

Another attempt to make pcre.h be found

v0.1.3

Move the binary optimization code to a separate proc

v0.1.2

Fix the asset file name

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