rigol-ds: Quick hack to fix bug #354.
Rename SR_T_CHAR to SR_T_STRING.

This is more correct and less confusing.
NEWS: Add list of user-visible changes so far.
configure.ac: Bump libtool/library version from 1:2:0 to 2:0:0.

The libtool current:revision:age numbers change from 1:2:0 to 2:0:0.

Details:
http://www.gnu.org/software/libtool/manual/libtool.html#Updating-version-info

This changes the library filename (e.g. on Linux) from libsigrok.so.1.0.2
to libsigrok.so.2.0.0, the SONAME (+symlink) becomes libsigrok.so.2.
configure.ac: Bump package version to 0.3.0.
motech-lps-30x: Initial driver framework.
strutil: Now using base 10 in sr_atol(), sr_atoi() for compatibility to atoi(), atol(); docs.
Whitespace and comment improvements, no semantical changes.
motech-lps-30x: Implemented driver.
motech-lps-30x: Cleanup.
motech-lps-30x: Cleanup.
fx2lafw: Rename trigger constant.
Add new triggering framework.

The new triggers consist of a set of structs and an API to manipulate
them.  Both logic and analog triggers are supported, in an unlimited
number of stages.

A single struct sr_trigger containing its stages and triggers is then
added to the session.

In case of a driver where the hardware supports triggering, the struct
is then converted and used to arm the hardware trigger. Drivers without
hardware trigger support, such as fx2lafw or multimeter drivers, use it
as the basis for a software-based trigger implementation instead.
Rename SR_CONF_TRIGGER_TYPE to SR_CONF_TRIGGER_MATCH.

Drivers supporting triggering need to implement this in config_list()
and return an array of int32_t consisting of SR_TRIGGER_*.
Remove obsolete API call sr_dev_trigger_set().

Triggers are now set on the session, not on a channel.
Remove obsolete API call sr_parse_triggerstring().

Since triggers are now passed to libsigrok with an API, this moved
to sigrok-cli.
Remove dead code from session read.

The "trigger" keyword was supported in theory, but in practice nothing
ever wrote it, so it was never used.
asix-sigma: Use new trigger API.
chronovu-la: Use new trigger API.
fx2lafw: Use new trigger API.