Make the lantern client claim 350MB of memory.
Launch smaller Digital Ocean instances.

RAM/$ for 512BM instance is the same as for 1GB, and other figures
grow linearly too.  Launching smaller ones gives us more granularity
(thus less expected underoccupation) and halves the impact of one
fallback malfunctioning or being blocked.
Merge branch 'master' of github.com:getlantern/lantern_aws