Reword replication introduction and image captions.

New flesch-ease: 19.146269620313944
Old flesch-ease: 6.62903861097621

New flesch-level: 16.59896558344934
Old flesch-level: 19.642037674321795
Clarify arbiter's role within a replica set with copy-editing.

replica-set-arbiter
New flesch-ease: 26.074225434492007 vs Old: 20.134938398357292
New flesch-level: 16.88124832887701 vs Old: 18.794657650640804

replica-set-members
New flesch-ease: 22.845720269272135 vs Old: 13.691667528772797
New flesch-level:16.495703565672844 vs Old: 19.769305142463043

replica-set-primary
New flesch-ease: 28.57250000000002 vs Old: 22.513859512251514
New flesch-level:15.66218253968254 vs Old: 17.58228328710125

replica-set-secondary.json
New flesch-ease: 16.458161392297512 vs Old: 5.042060427574199
New flesch-level:18.568842584724162 vs Old: 22.441420157068062
edits and readbility fixes to arbiters page:

Stats:

Before
---
file: build/master/json/core/replica-set-arbiter.json
source: source/build/master/json/core/replica-set-arbiter.txt
stats:
   coleman-liau: 10.170030581039754
   flesch-ease: 43.763087989991675
   flesch-level: 10.847796775090355
   foggy:
      count: 19
      factor: 0.0581039755351682
      threshold: 3
   sentence-count: 22
   sentence-len-avg: 14
   smog-index: 8.438071523408619
   word-count: 327

After
---
file: build/master/json/core/replica-set-arbiter.json
source: source/build/master/json/core/replica-set-arbiter.txt
stats:
   coleman-liau: 10.725673758865245
   flesch-ease: 44.78580000000002
   flesch-level: 9.81487375886525
   foggy:
      count: 18
      factor: 0.06382978723404255
      threshold: 3
   sentence-count: 25
   sentence-len-avg: 11
   smog-index: 7.976525956113203
   word-count: 282
edits+readability for replica-set-members:

Before:
---
file: build/master/json/core/replica-set-members.json
source: source/build/master/json/core/replica-set-members.txt
stats:
   coleman-liau: 11.510803324099722
   flesch-ease: 37.63714650661743
   flesch-level: 11.99558818097876
   foggy:
      count: 64
      factor: 0.0886426592797784
      threshold: 3
   sentence-count: 45
   sentence-len-avg: 16
   smog-index: 9.941947471260946
   word-count: 722

After:
---
file: build/master/json/core/replica-set-members.json
source: source/build/master/json/core/replica-set-members.txt
stats:
   coleman-liau: 11.326474622770917
   flesch-ease: 38.80385858585862
   flesch-level: 11.13976655443322
   foggy:
      count: 66
      factor: 0.09053497942386832
      threshold: 3
   sentence-count: 55
   sentence-len-avg: 13
   smog-index: 9.3871
   word-count: 729
DOCS-1641: fixing pdf urls
Copy edit for readability

NEW
---
stats:
   coleman-liau: 17.612799999999996
   flesch-ease: 12.257666666666665
   flesch-level: 14.862000000000002
   foggy:
      count: 35
      factor: 0.175
      threshold: 3
   sentence-count: 15
   sentence-len-avg: 13
   smog-index: 11.855464076750408
   word-count: 200

OLD
---
stats:
   coleman-liau: 20.837514124293786
   flesch-ease: -28.1897669491525
   flesch-level: 28.184166666666666
   foggy:
      count: 142
      factor: 0.20056497175141244
      threshold: 3
   sentence-count: 16
   sentence-len-avg: 44
   smog-index: 20.14790713358019
   word-count: 708
DOCS-1642: fixing syntax of geoWithin center queries
DOCS-1641: fixing links to pdfs
Copyedit replica-set-sync for readability

New stats:
   coleman-liau: 12.522114537444931
   flesch-ease: 43.28273984336761
   flesch-level: 10.35520558002937
   foggy:
      count: 50
      factor: 0.11013215859030837
      threshold: 3
   sentence-count: 36
   sentence-len-avg: 12
   smog-index: 9.861636050157227
   word-count: 454

Old stats:
   coleman-liau: 15.702144772117958
   flesch-ease: 12.785462609092491
   flesch-level: 19.362275397866636
   foggy:
      count: 209
      factor: 0.1400804289544236
      threshold: 3
   sentence-count: 47
   sentence-len-avg: 31
   smog-index: 15.175829255058439
   word-count: 1492
DOCS-1599 explicit mention of installing SASL dependencies in release notes
edit+readability: replica set sync

Before:
---
file: build/master/json/core/replica-set-sync.json
source: source/build/master/json/core/replica-set-sync.txt
stats:
   coleman-liau: 12.522114537444931
   flesch-ease: 43.28273984336761
   flesch-level: 10.35520558002937
   foggy:
      count: 50
      factor: 0.11013215859030837
      threshold: 3
   sentence-count: 36
   sentence-len-avg: 12
   smog-index: 9.861636050157227
   word-count: 454

After:
---
file: build/master/json/core/replica-set-sync.json
source: source/build/master/json/core/replica-set-sync.txt
stats:
   coleman-liau: 12.406396181384245
   flesch-ease: 42.69369466471633
   flesch-level: 10.662197243821698
   foggy:
      count: 38
      factor: 0.09069212410501193
      threshold: 3
   sentence-count: 31
   sentence-len-avg: 13
   smog-index: 9.454032385205343
   word-count: 419
edit+readability: rs architectures 4 or more members

After:
---
file: build/master/json/core/replica-set-architecture-four-members.json
source: source/core/replica-set-architecture-four-members.txt
stats:
   coleman-liau: 9.576623376623374
   flesch-ease: 50.61785714285716
   flesch-level: 9.677142857142858
   foggy:
      count: 24
      factor: 0.07792207792207792
      threshold: 3
   sentence-count: 22
   sentence-len-avg: 14
   smog-index: 9.095868883498916
   word-count: 308

Before:
---
file: build/master/json/core/replica-set-architecture-four-members.json
source: source/core/replica-set-architecture-four-members.txt
stats:
   coleman-liau: 9.641433224755698
   flesch-ease: 47.40719299674268
   flesch-level: 10.460343648208472
   foggy:
      count: 23
      factor: 0.0749185667752443
      threshold: 3
   sentence-count: 20
   sentence-len-avg: 15
   smog-index: 9.255337874911486
   word-count: 307
reducing arbiter context
DOCS-1644: inital fixes for mongofiles page
edits+concision: removing redundancy.

Before
---
file: build/master/json/core/replica-set-architecture-geographically-distributed.json
source: source/core/replica-set-architecture-geographically-distributed.txt
stats:
   coleman-liau: 8.94094674556213
   flesch-ease: 48.87059418145961
   flesch-level: 9.94155325443787
   foggy:
      count: 24
      factor: 0.07100591715976332
      threshold: 3
   sentence-count: 24
   sentence-len-avg: 14
   smog-index: 8.841846274778883
   word-count: 338

After
---
file: build/master/json/core/replica-set-architecture-geographically-distributed.json
source: source/core/replica-set-architecture-geographically-distributed.txt
stats:
   coleman-liau: 9.737249070631968
   flesch-ease: 42.87422552664191
   flesch-level: 10.461476367498673
   foggy:
      count: 24
      factor: 0.08921933085501858
      threshold: 3
   sentence-count: 21
   sentence-len-avg: 12
   smog-index: 9.236282656511921
   word-count: 269
edits+readability: rs-architectures

Before:
---
file: build/master/json/core/replica-set-architecture-three-members.json
source: source/core/replica-set-architecture-three-members.txt
stats:
   coleman-liau: 10.921875
   flesch-ease: 37.411988636363674
   flesch-level: 11.654602272727274
   foggy:
      count: 29
      factor: 0.090625
      threshold: 3
   sentence-count: 22
   sentence-len-avg: 14
   smog-index: 9.68802393474861
   word-count: 320

After:
---
file: build/master/json/core/replica-set-architecture-three-members.json
source: source/core/replica-set-architecture-three-members.txt
stats:
   coleman-liau: 9.932528735632186
   flesch-ease: 42.77184093437154
   flesch-level: 10.082317389692253
   foggy:
      count: 28
      factor: 0.08045977011494253
      threshold: 3
   sentence-count: 31
   sentence-len-avg: 11
   smog-index: 8.558390810932622
   word-count: 348
DOCS-1551 & 1552 clarifying how GeoJSON polygons work in Mongo & adding example

Signed-off-by: Sam Kleinman <samk@10gen.com>
DOCS-1551 and DOCS-1552: edits
rs-refactor: updating the deploy replica set tutorial