Springer Link concurrent implementation

[bfsc]

Implement the Springer Link search provider concurrently in order to access result pages in different threads improving the search performance.

Some sugesttions of eclipse plugins to analyse the reviewer performance:

1. JVM Monitor - Plugin for JVM profiling http://www.jvmmonitor.org/
2. Memory Analyzer - Plugin to analyze JVM memory dumps http://www.eclipse.org/mat/