Add blobs utility function to hesokuri.git

This makes it possible to process a tree more easily in some cases. For
instance, it lets you process a tree using reduce.
Add functionality to read-tree to automatically read blob contents

This will help code in hesokuri.hesobase read and interpret the config repo.
Add simple wrappers to hesokuri.util for percent encoding/decoding

This saves me from passing "UTF-8" explicitly and typing a long method name.
Add hesokuri.util/conj-in, similar to assoc-in
Implement hesokuri.hesobase/to-config

For converting the tree of a hesobase to a config structure, which is very
similar to what is already used in the flat configuration file.
Merge pull request #17 from matvore/config-convert

Conversion of hesobase repo tree to configuration structure