* Initial support of end Range header option in lfs

* Allow end range option to be unspecified

* Declare toByte for consistency

* Factor out content encoding tests from doLfs

This is so Range tests could still use doLfs but without repeating
not related tests

* Add Range header test

* implemented extraHeader
* parametrized expectedStatus

* Add more test cases of Range header

* Fix S1030: should use resp.Body.String()

* Add more tests for edge cases

* Fix tests

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: zeripath <art27@cantab.net>