use powi intrinsic for float^int. ref #6112

restores the performance of stockcorr
Add initial appveyor.yml
Make cygwin say hello
More info from Cygwin
Install make
Try cyg-get in powershell
Add C:\cygwin to path
Install make and split cyg-get onto multiple lines
Install dos2unix, run on relative_path.sh

try XC_HOST before make instead of after
Fix fortran typo
Split build commands into contrib/cygwin_build.sh
Create cygwin_build.sh
cyg-get default doesn't seem to work
try multi-package cyg-get again
run dos2unix on cygwin_build.sh
multi-package install doesn't work

try sourcing cygwin_build.sh
sourcing doesnt work either
d2u jldownload
Install wget and hush d2u
Make git fix the line endings