message: Update readme for signals
diff: @@ -26,7 +26,7 @@ Below is the help-text for a thorough explanation of the flags and features
  available:
  ```
  -cargo-tarpaulin version: 0.12.1
  +cargo-tarpaulin version: 0.12.2
  Tool to analyse test coverage of cargo projects
  USAGE:
  @@ -88,6 +88,14 @@ ARGS:
  <args>... Arguments to be passed to the test executables can be used to filter or skip certain tests
  ```
  +### Note on tests using signals
  +
  +If your tests or application make use of unix signals they may not work with
  +tarpaulin. This is because tarpaulin relies on the sigtrap signal to catch when
  +the instrumentation points are hit. The `--forward` option results in
  +forwarding the signals from process stops not caused by SIGSTOP, SIGSEGV or
  +SIGILL to the test binary.
  +
  ## Features
  Below is a list of features currently implemented. As Tarpaulin loads binary
  