vector: remove addVectorComponent as it doesn't have much of a use case
add vim swap files to ignore
vector: modify implementation to use an array
vector: use a typedef for the vector component data type
vector: remove lira_createEmptyVector

There's never any good use case for an empty vector. GONE!
vector: update brief doc on vector struct internals
vector: swap params in lira_setVectorComponent

This makes it consistent with its "get" counterpart.
vector: include assert header
vector: remove array subscript from vector component declaration
vector: update lira_createVector to work with new vector struct
vector: update lira_freeVector to use the new struct
add note about instability in README