Add Hamming-weighted average to DelayedAggregation

[juanmc2005]

Issue

This PR addresses issue #13, #17 and partly #15.

Changelog

• Decouple aggregation strategy from DelayedAggregation
• Add HammingWeightedAverageStrategy, AverageStrategy and FirstOnlyStrategy
• Rename strategy "any" to "first", which is more descriptive
• Replace UnreliableFileAudioSource in demo.py that was causing issues with ReliableFileAudioSource
• Fix bugs in ReliableFileAudioSource
• Add is_regular property to AudioSource to indicate whether a source should be regularized or not, for example in OnlineSpeakerDiarization pipeline
• Add optional duration property to AudioSource in order to output last non-aggregated predictions
• Replace buffer_with_count with custom buffer_slide operator
• Fix: initial predictions were being ignored because the number of buffers to aggregate didn't match the expected amount
• Fix: last latency - step seconds were being ignored in streamed files
• Make OutputBuilder draw as soon as the first buffer and adapt the visualization extents dynamically
• Add optional stream_end parameter to DelayedAggregation