cosmetic indent
loosen metrics test for VMs
a few more http constant strings
introduce specific exception for http parsing: http_parse_error
add a few more strings in hs::
json: use "explicit operator bool", distinguish true from truthy, use std::move() right, etc.
restore json() default ctor
provide json copy
quiet unused-var warning in strtod.cc
Merge pull request #71 from chipdude/master

collection of small improvements