If a class has a constructor which can be called with a single argument,
then this constructor becomes conversion constructor because such a
constructor allows conversion of the single argument to the class being
constructed. To ensure these constructors are passed the argument of its
type, I labeled them explicit.
In some header files, there were constructors that took a value that
could involve implicit conversions, so I added explicit to ensure that
does not happen.
This commit adds a debugging feature that can be activated by holding
down Left Alt _and_ Right Alt when a new tab is being created, if you
have the global setting "debugFeatures" set to true. That global setting
will default to true in DEBUG builds.
That debugging feature takes the form of a split pane that shows the raw
VT sequences being written to and received from the connection.
When those buttons are held down, every connection that's created as
part of a new tab is wrapped and split into _two_ connections: one to
capture input (and stand in for the main connection) and one to capture
output (and be displayed off to the side)
Closes#3206
