replace the FolderStorage with DiskStorage

- The DiskStorage uses only one file instead of millions.
  Also the block size is only 512 byte instead of 4kb, which
  helps to reduce the memory usage for short sequences.
- Update primitiveCollections to get the new LongList.range
  and LongList.rangeClosed methods.
- BSFile now stores Time&Value sequences and knows how to
  encode the time values with delta encoding.
- Doc had to do some magic tricks to save memory. The path
  was initialized lazy and stored as byte array. This is no
  longer necessary. The patch was replaced by the
  rootBlockNumber of the BSFile.
- Had to temporarily disable the 'in' queries.
- The stored values are now processed as stream of LongLists
  instead of Entry. The overhead for creating Entries is
  gone, so is the memory overhead, because Entry was an
  object and had a reference to the tags, which is
  unnecessary.

pdb-api/build.gradle

@@ -2,4 +2,5 @@
 dependencies {
 	compile project(':pdb-utils')
 	compile project(':file-utils')
+    compile 'org.lucares:primitiveCollections:0.1.20180908084945'
 }