Resolve runtime path

[tkf]

#183 needs to go first. It's still a WIP as I need to update the docs. But I want to check that it works on other platforms first.

[stevengj]

Good to go once docs are updated?

[coveralls]

Pull Request Test Coverage Report for Build 471

• 9 of 17 (52.94%) changed or added relevant lines in 1 file are covered.
• 12 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.7%) to 77.756%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
julia/core.py	9	17	52.94%

Files with Coverage Reduction	New Missed Lines	%
julia/find_libpython.py	4	78.15%
julia/core.py	8	83.54%

Totals
Change from base Build 469:	-0.7%
Covered Lines:	395
Relevant Lines:	508

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💛 - Coveralls

[tkf]

Rebased and added the docs. It's good to go now.