Robotics Service Bus

Improved Boolean support in parse-{payload,call}-spec common/event.lisp

refs #2070

`parse-payload-spec' and the new function `parse-call-spec' accept
"true" and "false" and report errors properly.

• common/conditions.lisp (call-specification-error): new condition;
  signal when parsing a call specification fails
• common/event.lisp (parse-payload-spec): accept "true" and "false" for
  Boolean values
  (parse-call-spec): new function; moved here from call/main.lisp; parse
  an RPC specification
• common/package.lisp (package rsb.common): added exported symbols
  call-specification-error, call-specification-error-specification and
  parse-call-spec
• test/common/event.lisp: new file; contains tests for event and payload
  parsing
• cl-rsb-common.asd (system cl-rsb-common-test): added file
  test/common/event.lisp
• call/main.lisp (make-help-string): mention "true" and "false"
  (main): use `parse-call-spec' for parsing and checking
• send/main.lisp (make-help-string): mention "true" and "false"
• CMakeLists.txt: added test cases with "true" and "false" payloads for
  call and send tools