template support to basePath

[Odi55555]

Adding grunt template support to basePath.
I'm not into grunt development, but this change works fine for me!
example usage:
manifest: {
generate: {
options: {
basePath: "<%= meta.version %>/",
...

[ghost]

<% %> style template strings specified as config data inside the Gruntfile are automatically expanded

This functionality is included in the core as of grunt v0.4, thanks anyway @Odi55555.