change json request content type

use correct content type for json requests "application/json", see
RFC4627
added fix for missing whitespaces after block elements
DefaultIndexAccessor: reopen reading readers on reopen()
added test for reopen reading readers
added test resources
added classpath resolving for portalnode confpath
added javadoc
Merge pull request #8 from sebastianvogel/dev-htmltransformer

HTMLContentTransformer: added fix for missing whitespaces after block elements
Merge pull request #9 from sebastianvogel/dev-reopenreader

DefaultIndexAccessor will now reopen also reading readers on reopen()
Merge pull request #10 from sebastianvogel/dev-classpathloader

Classpath resolving for confpath
fixed encoding
Merge pull request #11 from sebastianvogel/dev-json-contenttype

corrected json request content type
merged changes from gentics branch