Don't automatically catch exceptions when enabling Sentry support

[Vincent Bernat]

Hey!

When enabling Sentry support, uncaught exceptions are automatically intercepted. This is surprising for a library to take over exceptions and an application may want to do things differently and invoke capture! manually. Let the user opt-out (or opt-in) on exception catching.

[Pierre-Yves Ritschard]

Hi.

capture! can always be invoked manually. A flag to opt-out makes sense in case you already have one.

[Loic Lambiel]

+1 as we faced this issue in uri-dns

[Pierre-Yves Ritschard]

#9 provides an opt-out