Complex SV intervals support

[mwalker174]

• Complex (CPX) SV records no longer use END2/CHR2 INFO fields and instead are defined by CPX_INTERVALS in addition to normal coordinates.
• Adds new class SVCallRecord.ComplexEventInterval for storing complex event intervals, which are associated with a particular SV type.
• SV clustering now takes into account CPX subtype and intervals, requiring intervals to match on type and interval similarity as defined by the clustering parameters (e.g. minimum reciprocal overlap).
• Improved reciprocal translocation (CTX) record handling. In particular, these records are now treated similarly to BNDs for clustering purposes.
• Added unit tests for new CPX cases.