use pip install in conda-forge build scripts

Author: ndgrigorian

conda-recipe-cf/bld.bat

@@ -1,3 +1,2 @@
-set MKLROOT=%PREFIX%
-%PYTHON% setup.py build --force install --old-and-unmanageable
+%PYTHON% -m pip install --no-build-isolation --no-deps .
 if errorlevel 1 exit 1

conda-recipe-cf/build.sh

@@ -1,6 +1,3 @@
 #!/bin/bash -x
 
-# make sure that compiler has been sourced, if necessary
-
-export MKLROOT=${PREFIX}
-$PYTHON setup.py build --force install --old-and-unmanageable
+$PYTHON -m pip install --no-build-isolation --no-deps .