Implement Update. Related to #355
Fix for OS X
Add cog
Implement a slider
V2 for updates
Add db icon
Implement secondary indexes
Fix margin for whole list
s/for/to
Change style for link to release announcement
Improve secondary indexes. Less states are available
Handle empty string
Removed AIOSUPPORT from the code.
Got rid of pool_io_backender_t, made io_backender_t not be a hierarchy.
Detemplatized much of linux_templated_disk_manager_t, renaming it to linux_disk_manager_t.
Made linux_file_t take a scoped_fd_t by... rvalue reference!  Egads.
Removed unused io_backend_t type.
Fixed comment to no longer reference AIO backend.
Removed unused commented-out DEBUG_DUMP_WRITES #define.
Updated copyright notices.