Use PyCall.conda_add to install dependencies in deps/build.jl

see: JuliaPy/PyCall.jl#613

deps/build.jl

@@ -0,0 +1,27 @@
+in_CI = lowercase(get(ENV, "CI", "false")) == "true"
+
+if in_CI
+    # Let PyCall.jl use Python interpreter from Conda.jl
+    # See: https://github.com/JuliaPy/PyCall.jl
+    ENV["PYTHON"] = ""
+    Pkg.build("PyCall")
+end
+
+using PyCall
+
+packages = ["ipython"]
+if in_CI
+    push!(packages, "pytest")
+    if get(ENV, "CONDA_JL_VERSION", "") == "2"
+        # For IPython.testing.globalipapp
+        push!(packages, "mock")
+    end
+end
+PyCall.conda_add(packages)
+
+if VERSION >= v"0.7.0-"
+    @info "PyCall/deps/build.log:"
+    print(read(
+        joinpath(dirname(dirname(pathof(IPython.PyCall))), "deps", "build.log"),
+        String))
+end