bugfix conda render (#695)

* pin conda-built to newer version

* switch to curl for miniconda acquisition

* render+build the conda package on PRs, on master, and on tags, but only upload to anaconda.org on tags

* travis-trigger curl call is now silent, except on error

* move build-an-deploy script to after_success

deploy conditional is now in the script itself, so we can call it every
time

* placeholder version number for conda build test

* recipe render can now specify filename override to handle downloading file for branch

* bugfix conda render for tag case

packaging/conda-recipe/render-recipe.py

@@ -218,7 +218,7 @@ def url_md5(url):
     # store two separate version strings, one to use for the conda package and one
     # that should match github tagged releases
     recipe_variables["PKG_VERSION"] = str(args_dict.pop("version"))
-    if "src_download_filename" in args_dict:
+    if "src_download_filename" in args_dict and args_dict["src_download_filename"] is not None:
         recipe_variables["PKG_VERSION"] = str(args_dict.pop("src_download_filename"))
 
     # strip "v" prefix from versions that look like v1.14.0