Due to some quirky emergent behavior, the server can't really begin
synching until twice the default close time resolution of the genesis
ledger, which is 30 seconds, has passed. In effect, this causes a one
minute delay.
This commit adjusts the default close time resolution down to the
minimum allowed resoluion of 10 seconds, so the corresponding delay
is reduced by 67% down to 20 seconds. This should be enough time to
ensure the server has reasonable connectivity without unduly delaying
initial synch times.
At this point all of the jss::* names are defined in the same
file. That file has been named JsonFields.h. That file name
has little to do with either JsonStaticStrings (which is what
jss is short for) or with jss. The file is renamed to jss.h
so the file name better reflects what the file contains.
All includes of that file are fixed. A few include order
issues are tidied up along the way.
* Remove composite helper functions
* Add set difference and Bitset/uint256 operators
* Convert tests to use new feature bitset set difference operator
Enable all supported amendments in Env by default. Rename `features()`
to `with_features()` and add `all_features_except()` to support feature
subsets in Env. Refactor internal feature handling based on a bitset.