[rset] replace entity cw_rset on .limit(inplace=True) will avoid pb if the entity is still referenced by some other entity relations cache. Closes #2065643 Also, drop '_resultset' from some test names on the way (redundant information, we're in ResultSetTC...)

[instance creation] properly search for sql extension in the schema directory. Closes #2068117

[entity table view] add count default to true on main entity column

[table sort] should eval cubicweb:sortvalue to make it works properly

[rqlinput] cleanup (use req everywhere) and fix html validation issue (input outside fieldset)

[js table sort] use lower cased tag names since HTML is case insensitive and XHTML is case sensitive and wants lower case tag names