schema_version updated to 93

[ENSCORESW-2465] Fix comparisons in Exon::is_coding() to prevent fals…

[ENSCORESW-2465] Fix comparisons in Exon::is_coding() to prevent false-negatives when transcript and exon boundaries match exactly. Added additional transcript and translation structures to exon test cases.

[ENSCORESW-2325]. Temporary fix to take into account unavailability of next release DBs on the live server when adding the version upgrade to the following one. Also, switch to the default port.

[ENSCORESW-2612]. Send notification only when build status changes, on_success defaults to 'change' accoring to documentation.

[ENSCORESW-2595] Implement a dodge to avoid Travis-specific perl segfault around disconnect_if_idle(); At present the issue only appears in gene.t and we may presume it isn't affecting real use.

Broaden the net to see whether it is only perl 5.26 on the travis docker image which is failing gene.t

[ENSCORESW-1096]. Would be useful if the labels in POD would reflect the reality, but these have never been updated and have been out of date for a very long time.