switch haproxy to nginx for load balancing

Ignore-this: 54df2461e3118f414b95b2aac7972ea6

darcs-hash:20130804032825-312f9-4317cdea67cae56304650e1407a29cdec3d9fb0e
refactor webuser.py

Ignore-this: 8242df6cdcf1cf2a7eb5d64c7245cf17

darcs-hash:20130804075735-312f9-2a629597a98cd9c3922fd1ed18dc5dcbdd7db336
add more caching to ACL calculations. could be wrong after edits, now

Ignore-this: 9ed59183ad9aaf7eb803f5537872bdbb

darcs-hash:20130804075845-312f9-710a36cf1b49863fc591bc5aae058285d5a2da02
drop some old test uri paths

Ignore-this: c3e08affa1192cecd53faa1eacadb43e

darcs-hash:20130804080010-312f9-304b733a4698884d24ad1fb7179b68b3152a7edc
try least_conn in nginx

Ignore-this: 9d1c3f2cf60c77a1c83627ea23037bc7

darcs-hash:20130804080028-312f9-11a29bdde4f635cdb403da02a3d77d3eb54b05e4
fix randomSet infinite loop

Ignore-this: eb0a2a821ae389e691adc0187a2d5e97

darcs-hash:20130805072318-312f9-080cc03f093ec9501dbd41164217d8952e97dd60
nginx run with exec so it can be killed

Ignore-this: e8675c55f7aa7914f35cc71d9c918795

darcs-hash:20130805072357-312f9-6bb8d44f13f88698fab4dfa53233b4c0ad435a9d