adding missing get_field operation
adding different compose for bracket operator and nth, slice, and get_field, depending on how the query was invoked
Add v8 to make dist

Review 1193
Closes #1844
Use HTTP instead of HTTPS for fetching v8

Older versions of wget complain about an invalid certificate.

Review 1194 by @mlucy
Do not use offsetof in wire_string.cc

GCC 4.4 complains about it.

Review 1190 by @danielmewes
Closes #1936
Made tracker_acq_t be updated when a page is dirtied.
Merge branch 'next' into sam_alt