Don't swallow exceptions -- throw them up instead

[stellingsimon]

Exceptions, and in particular IOException in networking code, should not be swallowed but thrown up to the caller, such that an appropriate error message can be generated for the end user. The client is still free to wrap all ical4j-Methods in a catch-all try-catch.

I made a fairly mechanic change to all the catch clauses:

• replace e.printStackTrace() with throw new RuntimeException(..., e) for all checked exception's catch clauses.
• remove catch clauses for NullPointerException in AbstractDavObjectCollection::getProperty(DavPropertyName propertyName, Class<P> type)
• throw UnsupportedOperationException(...) in obviously unimplemented methods
• No method signatures were changed

[codecov]

Codecov Report

Merging #17 into develop will increase coverage by 0.14%.
The diff coverage is 0%.

@@             Coverage Diff              @@
##             develop     #17      +/-   ##
============================================
+ Coverage       1.74%   1.88%   +0.14%     
  Complexity         5       5              
============================================
  Files             44      44              
  Lines           2008    1852     -156     
  Branches         256     255       -1     
============================================
  Hits              35      35              
+ Misses          1973    1817     -156

Impacted Files	Coverage Δ	Complexity Δ
...una/ical4j/connector/FailedOperationException.java	0% <ø> (ø)	0 <0> (ø)	⬇️
...net/fortuna/ical4j/connector/dav/CardDavStore.java	0% <0%> (ø)	0 <0> (ø)	⬇️
...l4j/connector/dav/AbstractDavObjectCollection.java	0% <0%> (ø)	0 <0> (ø)	⬇️
...ortuna/ical4j/connector/dav/CardDavCollection.java	0% <0%> (ø)	0 <0> (ø)	⬇️
...tuna/ical4j/connector/dav/CalDavCalendarStore.java	0.77% <0%> (+0.01%)	1 <0> (ø)	⬇️
...ical4j/connector/dav/CalDavCalendarCollection.java	0% <0%> (ø)	0 <0> (ø)	⬇️

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