Installation instructions for any installation directory.
Installation instructions for any installation directory.

Updated README.md contents so that installation instructions cover
not only the common case for installation directory, i.e. `~/.pyenv`
but any other at the user's choice.

hlecuanda/pyenv,yyuu/pyenv,habinmusic/pyenv,yeonsh/pyenv,chenfengyuan/pyenv,pyenv/pyenv,rowhit/pyenv,syndbg/goenv,yeonsh/pyenv,BanzaiMan/pyenv,obimod/pyenv,sebhahn/pyenv,fly19890211/pyenv,obimod/pyenv,xshwy/pyenv,genome-vendor/pyenv,UCASREN/pyenv,pyenv/pyenv,lepture/pyenv,VShangxiao/pyenv,recruit-mtl/pyenv,yyuu/pyenv,zmwangx/pyenv,UCASREN/pyenv,dongguangming/pyenv,recruit-mtl/pyenv,dnsd/pyenv,pyenv/pyenv,syndbg/goenv,kevinburke/pyenv,syndbg/goenv,habinmusic/pyenv,zmwangx/pyenv,blueyed/pyenv,VShangxiao/pyenv,hlecuanda/pyenv,xshwy/pyenv,lozybean/pyenv,fly19890211/pyenv,dnsd/pyenv,genome-vendor/pyenv,cehoffman/pyenv,cehoffman/pyenv,BanzaiMan/pyenv,dongguangming/pyenv,takluyver/pyenv,takluyver/pyenv,chenfengyuan/pyenv,kevinburke/pyenv,rowhit/pyenv,syndbg/goenv,lozybean/pyenv,sebhahn/pyenv,sebhahn/pyenv,lepture/pyenv