Enhancements:
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* Warn user about path conflicts during environment building for test phase  #2843
* Add conda 4.6 compatibility   #2844
* **remove conda 4.2 and earlier compatibility**  #2845
* add info to merge/copy source subdir error  #2858
* Add setup for Air Speed Velocity benchmarking  #2859

Bug fixes:
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* fix python handling when python is a tuple (inner python looping)  #2854
* fix python not looping in inner packages when top-level doesn't use it.  Fix zip_keys handling. #2856

Contributors:
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* @kalefranz
* @msarahan