Merge pull request citusdata#51 from citusdata/small-improvements

Small improvements in README and build matrix

Author: Burak Yücesoy

.travis.yml

@@ -6,6 +6,7 @@ env:
   - PGVERSION=9.3
   - PGVERSION=9.4
   - PGVERSION=9.5
+  - PGVERSION=9.6
 before_script:
   - export PATH=/usr/lib/postgresql/$PGVERSION/bin:$PATH     # Add our chosen PG version to the path
   - sudo /etc/init.d/postgresql stop                         # Stop whichever version of PG that travis started

README.markdown

@@ -37,7 +37,7 @@ Our motivation for augmenting the original HLL algorithm went something like thi
 
 The first addition to the original HLL algorithm came from realizing that 1,280 bytes is the size of 160 64-bit integers. So, if we wanted more accuracy at low cardinalities, we could just keep an explicit set of the inputs as a sorted list of 64-bit integers until we hit the 161st distinct value. This would give us the true representation of the distinct values in the stream while requiring the same amount of memory. (This is the `EXPLICIT` algorithm.)
 
-The second came from the realization that we didn't need to store registers whose value was zero. We could simply represent the set of registers that had non-zero values as a map from index to values. This is map is stored as a list of index-value pairs that are bit-packed "short words" of length `log2m + regwidth`. (This is the `SPARSE` algorithm.)
+The second came from the realization that we didn't need to store registers whose value was zero. We could simply represent the set of registers that had non-zero values as a map from index to values. This map is stored as a list of index-value pairs that are bit-packed "short words" of length `log2m + regwidth`. (This is the `SPARSE` algorithm.)
 
 Combining these two augmentations, we get a "promotion hierarchy" that allows the algorithm to be tuned for better accuracy, memory, or performance.
 
@@ -180,7 +180,7 @@ We've added a few operators to make using `hll`s less cumbersome/verbose. They'r
 Hashing
 -------
 
-You'll notice that all the calls to `hll_add` or `||` involve wrapping the input value in a `hll_hash_[type]` call; it's aboslutely crucial that you hash your input values to `hll` structures. For more on this, see the section below titled 'The Importance of Hashing'.
+You'll notice that all the calls to `hll_add` or `||` involve wrapping the input value in a `hll_hash_[type]` call; it's absolutely crucial that you hash your input values to `hll` structures. For more on this, see the section below titled 'The Importance of Hashing'.
 
 The hashing functions we've made available are listed below: