Cooja: allow setting RSSI while sending and silence

It is now possible to set the RSSI while the radio is sending or when
no radiodata is received. This is now supported by all radiomediums
exept MRM. This also includes a GUI to configure the values.
Added support to program Z1 far memory with BSL
Remove duplicated configuration parameters definition
Fix Travis failure

For travis tests, we host pre-built bundles of the arm-gcc and sdcc
toolchains on github, and we download them with curl

Apparently, the URL for those bundles has been changed and the
HTTP response is a 301 redirect. curl doesn't follow it

We change .travis.yml to pull the bundles form the new location
Merge pull request #662 from g-oikonomou/travis-url-fix

Fix Travis failure
Fix exported simulation: add jsyntaxpane JAR, start simulation with maximum speed
Merge pull request #663 from jdede/fix-cooja-export

Fix exported simulation: add jsyntaxpane JAR, start simulation
Merge pull request #450 from darki2002/DGRM_support_BaseRSSI

Base RSSI support for DGRM
Merge pull request #651 from cetic/pr-rpl-private-cleanup-fix

Remove duplicated RPL configuration parameters definition
Merge pull request #630 from blemmens/z1-bsl-far-memory-support

Added support to program Z1 far memory with BSL
Merge remote-tracking branch 'main/master' into coap-18