Clarify compiler exports in tasks readme
Export method to get resolution for extent and size

While this is straightforward to calculate, this method adds convenience.
Merge pull request #2141 from probins/patch-5

Clarify compiler exports in tasks readme.
Merge pull request #2142 from tschaub/res-for-extent

Export method to get resolution for extent and size.
Apidoc readme: clarify exportable methods
Merge pull request #2140 from probins/patch-3

Apidoc readme: clarify exportable methods.