Revert "Fix version numbers to be 5.0.0-rc1 instead of 5.0.0-RC1"

This reverts commit 4d37652886ba5e0f45977598e5f66b75e218db1b.
Revert "Switch 5.0.0-beta2 version numbers to 5.0.0-RC1"

This reverts commit 508b8346e0747635e3a7614c3de640e3606d9621.
Revert "Update POM version numbers to 5.0.0-beta2"

This reverts commit 2ade8fd70a4927adfbdf5ca884a312b12894a37f.
Fix version numbers to be 5.1.0-SNAPSHOT instead of 5.0.0-SNAPSHOT

The develop branch is 5.1.0-SNAPSHOT; the dev_5_0 branch is 5.0.0-SNAPSHOT.
Merge pull request #835 from melissalinkert/revert-version-number

Set POM versions to 5.1.0-SNAPSHOT
Initial ome-jpegxr project structure.
Align names, disable tests for now.
Rename component to ome-jxr, add tests.
Slight refactoring of tests and reader.
Remove "x" attribute from test file.
Add encoder version check and tests.
Fix Maven build.
Simplify endianness detection logic.
Add IFD getter and refactor tests.
Set the stream byte-order in ctor.
Further refactoring and test additions.
Another round of major refactoring.
Initial impl of metadata extraction.
Make metadata extraction almost work.
Clean up tests, comments; add close() method.