More additions to 2.7 Release Notes

Additions include a brief description of the web client preview, the
addition of Sprint 1 funding partners in the acknowledgements section,
the addition of NC Cardinal in the acknolwedgements section for
funding an acq funds transfer fix, and the addition of another code
contributor whose patch was just merged over the past few days.

Signed-off-by: Kathy Lussier <klussier@masslnc.org>
Signed-off-by: Ben Shum <bshum@biblio.org>
More additions to 2.7 Release Notes (part 2)

Add Steve Callender and move Yamil Suarez to the correct position alphabetically.

Also, note the location of the web client README.install file, but also
promise to update this by the next minor release of 2.7 series as a new
section of the primary README file.

Signed-off-by: Ben Shum <bshum@biblio.org>